|Year : 2014 | Volume
| Issue : 1 | Page : 8-12
A case-control study to evaluate salivary cortisol levels in patients with dry mouth
Vandana Shekar1, Ravi David Austin2, Phillips Mathew2
1 Department of Oral Medicine and Radiology, Indira Gandhi Institute of Dental Sciences, Puducherry, India
2 Department of Oral Medicine and Radiology, Rajah Muthiah Dental College and Hospital, Annamalai University, Chidambaram, Tamil Nadu, India
|Date of Submission||01-Jul-2014|
|Date of Acceptance||25-Jul-2014|
|Date of Web Publication||26-Sep-2014|
Department of Oral Medicine and Radiology, Indira Gandhi Institute of Dental Sciences, MGMC and RI Campus, Pillaiyarkuppam - 607 402, Puducherry
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: The purpose of this study is to evaluate the salivary cortisol levels in patients with dry mouth. Materials and Methods: The study population consisted of 20 patients with a complaint of dry mouth and 20 asymptomatic age- and sex-matched controls. In patients who complained of dry mouth, the salivary flow rate (ml/minute) was estimated by measuring the quantity of the saliva collected in the collector. The concentration of cortisol in the saliva (΅g/dl) was determined by using a salivary enzyme-linked immunoassay (ELISA) kit. Statistical Analysis: The results were evaluated using the Student's t-test. Results: There was only a mild increase in salivary cortisol in both stimulated and unstimulated saliva in patients with dry mouth compared to the controls (p-value 0.981 and 0.481, respectively), which was not statistically significant. Conclusion: There may not be a clear association between the salivary cortisol level and dry mouth. In older individuals, age-associated salivary gland hypofunction and life changes may be the main risk factors for dry mouth compared to stress and anxiety.
Keywords: Enzyme-linked immunosorbant assay, stimulated saliva, unstimulated saliva, xerostomia
|How to cite this article:|
Shekar V, Austin RD, Mathew P. A case-control study to evaluate salivary cortisol levels in patients with dry mouth
. J Indian Acad Oral Med Radiol 2014;26:8-12
|How to cite this URL:|
Shekar V, Austin RD, Mathew P. A case-control study to evaluate salivary cortisol levels in patients with dry mouth
. J Indian Acad Oral Med Radiol [serial online] 2014 [cited 2020 Jan 26];26:8-12. Available from: http://www.jiaomr.in/text.asp?2014/26/1/8/141824
| Introduction|| |
Xerostomia or 'dry mouth' is the result of inadequate saliva in either quantity of flow or quality of saliva. It is also known as salivary gland hypofunction. Xerostomia is not a disease, it is a symptom.
With regard to depression and its relationship with xerostomia, various studies have used different tests to evaluate the psychological condition, establishing a direct relationship between these variables, both with the appearance of the symptoms and with its disappearance on the improvement of the depression. 
The cortisol level in the serum or saliva has been shown to be a reliable indicator of stress. Cortisol is produced by the adrenal glands and is an important hormone for normal health. Normally cortisol is secreted with a distinctive daily pattern called 'a circadian rhythm' - cortisone levels peak in the morning (between 7 and 8 a.m.) and decrease to substantially lower levels late at night. Salivary cortisol is an accurate reflection of the free, biologically active portion of cortisol in the blood. Salivary measures of cortisol have been shown to be a valid and reliable reflection of serum cortisol.  Some authors state that salivary cortisol may actually provide a better measure of the stress response than serum cortisol, as its measures of the amount of the unbound cortisol are more accurate compared to the serum cortisol measures.  In general terms, differences in salivary cortisol seem to exist between depressed patients and healthy individuals.  For this reason, salivary cortisol levels could be used as a non-invasive biological marker for changes like xerostomia related to anxiety and depression, and although its predictive value is controversial, this possible relationship would be a relevant finding for the multidisciplinary management of these patients. Considering these facts and the prevalence of xerostomia in patients with anxiety and depression, the purpose of this study is to evaluate those patients with a subjective sensation of dry mouth, who presented with modifications in salivary cortisol, and to compare them with those patients who did not complain of dry mouth.
| Aims and Objectives|| |
To evaluate the salivary cortisol levels in patients with dry mouth.
- To establish a correlation between unstimulated salivary flow rate and salivary cortisol level in patients with a dry mouth.
- To establish a correlation between stimulated salivary flow rate and salivary cortisol level in patients with a dry mouth.
- To investigate the correlation between hyposalivation and salivary levels of cortisol in patients with a dry mouth.
| Materials and Methods|| |
In the present study, 20 patients with subjective symptoms of dry mouth and objective signs such as positive tongue blade sign and ropy saliva, who visited the Department of Oral Medicine and Radiology were considered as the study group and compared with 20 age- and sex-matched controls with normal salivation. Patients with Sjogren's syndrome, connective tissue disorder, patients on chemotherapy and radiotherapy, patients on therapy for mental illness, subjects on corticosteroid therapy, patients on xerogenic drugs, and patients with diabetes mellitus were excluded from the study. Both the study and control groups were grouped into three groups (below 35 years, 36 to 40 years, and above 40 years).
A detailed case history was recorded with special reference to the complaint of dry mouth. In patients who complain of dry mouth, when the flat surface of a tongue blade was placed on the buccal mucosa and lifted away, it was noted that the tongue blade adhered to the mucosa. Saliva was allowed to pool below the tongue and the saliva was lifted with the sharp end of a probe; it was noted that in patients with dry mouth the saliva was stringy. The patients were given appointments the next morning and were asked to refrain from eating, smoking, brushing, and oral hygiene procedures two hours before collection of saliva.
To obtain the samples of unstimulated saliva from both groups, sterile disposable plastic collectors were used. Prior to taking the sample, the patients had a mouthwash of water in order to eliminate any possible debris and obtain a clean sample. The patients were then instructed to pool saliva in the floor of the mouth for one minute and then expectorate it into disposable plastic collectors. The saliva collected was then transferred to coded collection tubes, graduated in milliliters. The collected sample was placed in ice and the salivary flow rate (ml/minute) was estimated by measuring the quantity of the saliva collected in the collector. Thereafter, the samples were frozen at −30°C until further analysis.
To obtain samples of stimulated saliva, patients of both the groups were asked to chew sugarless chewing gum for five minutes at a constant pace of 60 times per minute, after which the entire saliva was expectorated into sterile plastic collectors, which were placed in ice immediately and the salivary flow rate (ml/minute) was estimated by measuring the quantity of saliva collected in the collector. The samples were frozen at −30°C until further analysis.
The concentration of cortisol in the saliva (μg/dl) was determined by using a salivary cortisol enzyme immunoassay kit with a lower sensitivity of 0.36 μg/dl. Before starting the test, all the samples were brought to room temperature and mixed well. All the reagents and the samples were kept ready and the test was started. The desired number of coated wells was secured in the holder. Ten microliters of salivary samples were dispensed into the appropriate wells. One hundred microliters of cortisol enzyme conjugate was dispensed into these wells and they were incubated for 60 minutes at room temperature. The incubation mixture was removed and the wells were rinsed with washing buffer five times. 3,3', 5, 5'-Tetramethylbenzidine (TMB) solution of 100 μL was dispensed into each well. The above wells were incubated for 30 minutes at room temperature. The reaction was then stopped by adding 50 μL of 2N HCL to each well, and the optical density (O.D.) was read at 450 nm with a microwell reader in minutes. The values were recorded and subjected to statistical analysis.
The paired Student's t-test was applied to identify the statistically significant correlation between stimulated and unstimulated saliva in patients with a dry mouth.
| Results|| |
The results of the study revealed that although the mean cortisol level in unstimulated saliva was slightly higher (2.01) in the study group when compared to the control group (1.99), it was not statistically significant. Estimation of the cortisol levels in the stimulated saliva of both the control and study groups revealed a slight increase in the mean cortisol level in the study group (1.75), as compared to the control group (1.46), although the results were not statistically significant.
Thus, there was only a mild increase in the salivary cortisol in both the stimulated and unstimulated saliva in patients with dry mouth compared to their controls (P-value 0.981 and 0.481, respectively), which was not statistically significant. The mean for the quantity of unstimulated saliva was higher (1.99) in the control group when compared to the study group (0.55). The quantity of stimulated saliva (3.71) was higher in the control group when compared to the study group (1.91).
| Discussion|| |
A number of reports have shown that salivary cortisol is associated with depression and anxiety, , and hence, salivary cortisol can be used as an important noninvasive biological indicator of stress.  In the present study, we aimed to evaluate the salivary cortisol levels in patients with xerostomia. Considering the age of the patients, in our study, a majority of the patients were above 40 years of age (50%) [Figure 1], which was in accordance with a recent systematic review of a population-based research, which suggested a higher prevalence of xerostomia in the older population.  Increasing age has been shown to correlate with a higher prevalence of xerostomia, as certain types of xerogenic drugs happen to be used more in the elderly population; however, in our study, we have excluded patients who are on routine use of xerogenic drugs. Age-associated salivary gland hypofunction and life changes may be one more reason for the higher prevalence of xerostomia in older patients. In our study, a majority of the respondents in the study group were females 65% [Figure 2]. This was in agreement with the previous studies. , Xerostomia may develop incrementally at different rates between males and females or may be caused by major life changes. Increased salivary flow rates in females may be due to differences in exposure to xerogenic medications or life changes such as menopause.  As patients using xerogenic drugs were excluded from the study group, life changes like menopause could be responsible for the female predilection. Previous studies assessing salivary levels of cortisol in patients with dry mouth  showed that the levels of salivary cortisol were increased in the study group when compared to the controls. However, in our study, although there was a mild increase in the level of cortisol in both unstimulated and stimulated saliva in the experimental group when compared to the control group [Figure 3] and [Figure 4], it was not statistically significant. Studies carried out to evaluate the association between the cortisol level and depression/anxiety found no clear association between those two parameters. , The prevalence of xerostomia increases with age and is approximately 30% in those aged 65 years and older.  This finding was in accordance with our findings [Figure 5] and [Figure 6].
|Figure 5: Mean for volume of unstimulated saliva in study and control group|
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|Figure 6: Mean for volume of stimulated saliva in study and control group|
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To the best of our knowledge only few known studies have documented the association between the pathophysiology of xerostomia and stress-related hormones. One study  compared the levels of salivary cortisol and the presence of xerostomia in menopausal women and found no significant association. Their findings were similar to the results of our study.
There are a few limitations, which we observed in this study. First, saliva sampling should have been performed earlier in the morning for a more accurate determination of the underlying physiological condition. Second, data regarding the salivary levels of stress-related hormones were obtained only from subjects able to produce an adequate quantity of measurable saliva with stimulation. However, because the salivary hormone assay kits used in the present study were capable of measuring saliva quantities as low as 50 μL, measurements of the biomarkers should be possible in most subjects, even those with severe hyposalivation. Third, whether the present biomarkers were useful as predictors for dry mouth remained unclear, because the design of the present study was cross-sectional.
| Conclusion|| |
It was concluded from the study that there was no statistically significant difference in the cortisol levels of unstimulated saliva of the experimental and control groups and there was no statistically significant difference in the cortisol levels of stimulated saliva of the experimental and control groups. This suggested that there might not be a clear association between the salivary cortisol level and dry mouth.
In older individuals, age-associated salivary gland hypofunction and life changes may be the main risk factors for dry mouth compared to stress and anxiety. However, considering the non-invasive nature and simplicity of the specimen collection, salivary cortisol estimation is a useful diagnostic modality in stress-related disorders.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]